Sequence from low reactor has been released. Most bizarre NA sequence I have ever seen.
??? Please explain this one?

niman wrote:

I have checked this twice and got the same result. A low reactor is a virus that doesn’t react well with the sera generated against the vaccine target (the virus has evolved away from the original sequence used to make the vaccine). This is the first signal that the vaccine will fail.

The HA and NA sequences were released. The HA sequence had two nucleotide changes, which were silent, so they wouldn’t change the reactivity.

The NA nucleotide sequence had over 110 changes (some regions had so many changes that the sequences wouldn’t allign). Thus, I expected to see MANY changes at the NA protein level which caused the low activity.

However, ALL of the changes were silent, so the protein sequence was the same. Thus, it is unclear why the activity with the antisera is low, and is unclear how the NA sequence can have so many silent changes.